1. Field of the Invention
The present invention relates to an automatic focus adjustment device with a focus state detection device, and in particular, to a photoelectric conversion device having multiple areas in which the accumulation time interval of one of the areas is matched to the accumulation time interval of another area.
2. Description of Related Art
Within the field of focus state detection devices using phase difference detection, a focus state detection device of the type that includes an electric charge accumulation photoelectric conversion device having a plurality of pairs of detection areas is known. In particular, the photoelectric conversion device of this type of focus state detection device is a CCD, MOS, or other similar component. In a first known method for controlling the electric charge accumulation photoelectric accumulation device, the accumulation time interval for each area is determined completely independently of the other. In a second known method, the accumulation starting times for each area are determined to be the same. In a third known method, the accumulation ending times for each area are determined to be the same.
A focus state detection device using an electric charge accumulation type of photoelectric conversion device having a pairs of detection areas detects the average object imaging plane position repeatedly during the accumulation period. The conventional accumulation control methods described above require that the accumulation midpoint time (i.e., the time midway between the starting time and the ending time) for each of the areas be recorded. As a result, a large volume of recorded data is generated as the number of areas increases. In addition, if the accumulation midpoint times differ, e.g., as shown in FIG. 4, determining whether the image extending over row AB and row CD is a single object or two separate objects is impossible.